POMONA, Calif. – A wrong-way driver on a Southern California freeway was arrested on suspicion of drunken driving after causing a pre-dawn crash with multiple vehicles Sunday that left six people dead, the California Highway Patrol said.

Police arrested the 21-year-old female driver on suspicion of felony driving under the influence and felony manslaughter in connection with the 4:40 a.m. accident on the westbound Pomona freeway, or State Route 60, in Diamond Bar, said Rodrigo Jimenez, a California Highway Patrol spokesman on the scene, who spoke to the Los Angeles Times, (http://lat.ms/1fQrEWe).

The female driver was in serious condition at a Los Angeles County hospital with a broken femur and a ruptured bladder, Jimenez said.

Authorities were seeking blood tests.

Investigators "believe from what they found in the vehicle that alcohol was involved," Los Angeles County Coroner's Lt. Fred Corral told the newspaper.

Jimenez said the woman was traveling east in a red Chevy Camaro when it collided head-on with a red Ford Explorer. The sequence of events involving the other vehicles was not immediately clear. At least two people were ejected from their vehicles, Jimenez said.

Four people were pronounced dead at the scene, and two people died at an area hospital, authorities said. The freeway lanes in both directions were closed for hours Sunday.

Jimenez told the newspaper as he stood near the crumpled vehicles that it was "a horrific collision."